Mononucleosis in Teens FAQ

Medically Reviewed by Dan Brennan, MD on February 15, 2024
Written by Kelli Miller
4 min read

Heard about a friend who's got mono? Here are some quick facts about mononucleosis.

  • It's an infection caused by a virus (the Epstein-Barr virus or EBV).
  • Mono is very common in teens.
  • Mononucleosis is contagious! If you've got mono, you can spread it to others.

Sometimes you can have mono and not even know it. Young kids usually have pretty mild symptoms. But teens can have more severe symptoms.

Symptoms of mono include:

Symptoms usually occur about four to six weeks after you come in contact with the virus.

Your doctor will examine you and check your neck for lumps or bumps. You will be asked questions about your symptoms. Make sure to tell the doctor about all your symptoms.

Your doctor may do some blood tests, including:

  • A monospot, which confirms that you've got mono. Blood tests that look for EBV antibodies and liver function tests can also help with a diagnosis of mono.
  • A CBC (complete blood count) will show if your lymphocytes, a type of white blood cell, show certain changes that may be a sign of mono.

There is no cure for mono. The virus eventually goes away, but it can take a few weeks.

Antibiotics are NOT used to treat mono. That's because mono is caused by a virus, and antibiotics do not kill viruses.

Once in a while, the doctor may prescribe drugs called steroids. This medicine is usually taken for about five days. It can help control swelling in the throat and tonsils.

Your doctor or nurse will recommend the following steps to make you feel better:

  • Get plenty of rest. Sleep helps your body fight the infection.
  • Avoid contact sports as well as other activities until your doctor says it's OK. This helps protect your spleen. A hit or fall could make it break open, or rupture. A ruptured spleen causes internal bleeding, which is a life-threatening condition.
  • Drink a lot of fluids. If your body does not have enough water, you can become dehydrated. Dehydration can make you feel worse.
  • Rinse your mouth or gargle with salt water. This can help soothe a sore throat. You can also try sucking on hard candy or eating a Popsicle.
  • Take acetaminophen (Tylenol) or ibuprofen (Advil, Motrin) for aches and pains. Do NOT take aspirin because of the risk of Reye syndrome, a rare but serious condition that typically affects people ages 4 to 14 who are recovering from chickenpox or another viral illness.

Most of the time, mono symptoms get better within a few weeks. But be patient. It can take a little bit of time. Symptoms of mono can linger for weeks or even months.

If you don’t feel better in a few weeks, you'll need to go back to the doctor.

Even when you feel better, you will still need to avoid strenuous activity for about a month. Your spleen needs this time to heal.

People rarely die from mono. But some complications of mono can be life threatening. One complication of mono is a ruptured spleen. Seek medical help right away if you have any of the following symptoms of a ruptured spleen:

  • Sharp pain in the upper left side of your belly near the ribs
  • Confusion
  • Fainting or feeling light-headed

Other rare complications are:

If you have a weakened immune system, you are more likely to have severe mononucleosis. Certain diseases and medicines can weaken the immune system. This includes HIV/AIDS, chemotherapy for cancer treatment, and steroids.

Mono most often spreads by kissing. That's because the virus that causes mono can be found in your mouth. It lives in saliva (spit) and mucus.

When you kiss someone, you are mixing your saliva with theirs. If you have mono and share saliva, you are sharing the virus, too. Kissing or having sex with someone with mono makes you more likely to get the infection.

Besides kissing, you may also catch mono if you:

  • Are near someone with mono who coughs or sneezes
  • Drink out of the same glass as someone with mono
  • Share a fork, spoon, or straw with someone who has mono

A good tip to remember is NEVER share eating utensils, water bottles, or drinking glasses. Following this rule can help lower your risk of getting mono.